Every once in a while, an app will show up in the iOS App Store that's not meant to be there, obviously in violation of one rule or another but overlooked by Apple's approval team. Here are 10 great iPhone apps that Apple banned from existence.

iTether

iTether, which enjoyed a few hours in the App Store this week, allowed the iPhone to become a portable modem, feeding Internet service to any laptop through a USB cable. For a one-time fee of $15, iTether was a steal compared to the $20 per month charged by AT&T and Verizon and the $30 per month charged by Sprint.

Violation: Carriers forbid unauthorized tethering in their terms of service, so iTether was never going to last.